Plants, as well as animals, repsond to changes in the environment. Plant hormones are chemicals that control:
- the growth of shoots and roots
- flowering and the ripening of fruits
One group of plant hormones called auxins move through the plant in solution. They affect the plant's growth by responding to gravity (geotropism) and light (phototropism).
- towards light (positive phototropism).
- against gravity (negative geotropism)
- away from light (negative phototropism)
- downwards in the direction of gravity (positive geotropism) to absorb water and provie support for the plant.
Auxin is made in the shoot tip. Its distribution through the plant is determined by light and…